Air conditioning system



July 26, 1938. I w. E. STARK ET AL 2,124,932

AIR CONDITIONING SYSTEM Filed Jan. 6, 1936 v 2 Sheets-Sheet 1 ATTORNEYEJuly 26, 1938.

w. E". STARK ET AL AIR CONDITIONING SYSTEM Filed Jan. 6, 1936 2Sheets-Sheet 2 INVENTOR.

BY JAMES 68477-57730 A nfifi Patented July 26, 1938 Am conmrromc SYSTEMWillet E. Stark, East Cleveland, and James 0. Patterson, Shaker Heights,Ohio, asslgnors to The Bryant Heater Company, Cleveland, Ohio,

a corporation of Ohio Application January 6, 1936, Serial No. 57,668

11 Claims.

This invention relates to improvements in air conditioning systems,particularly systems employed in localities or climates where theprincipal requirement is for dehumidification with more or less cooling,and where heating requirements are infrequent, relatively small and ofcomparatively short duration.

One of the objects of the invention is the utilization of a dehumidifieras a means for heating the premises,

Another object is the provision of an air conditioning system which willrespond quickly and automatically to changes in atmospheric conditions,and particularly to a system in which the small amount of occasionalheating that is needed is accomplished by the same equipment that isordinarily used for dehumidifying without in any way changing theoperation of that equipment.

Another object is the provision of means for controlling automaticallythe operation of a dehumidifier of the adsorption type and associatedapparatus, so as to cause the same to supply dry air cooled to roomtemperature when the temperature in the premises is high enough forcomfort, or dry heated air when the temperature is below the desiredstandard, th'e heat being principally heat of vaporization convertedinto sensible heat by the dehumidifier.

A further object is the provision of means for utilizing heat resultingfrom the dehumidifylng action and the reactivation process to heatwater, or to perform other useful work.

Other objects and features of novelty will appear as we proceed with thedescription of that embodiment of the invention which, for the purposesof the present application, we have illustrated in the accompanyingdrawings, in which Fig. 1 is a diagrammatic view of an air conditioningsystem employing a dehumidifier of the adsorption type and embodying thepresent invention.

Fig. 2 is a wiring diagram showing control circuits for the apparatus,and

Fig.3 is a detail elevational view of a humidostat which may be used inconnection with the invention.

The air conditioning system comprehended by this invention is designedto take care of all consuch character that heat is released in theproc-' ess of dehumidification, so that the air passing through thedehumidifier emerges in a warm state. For this purpose we prefer toemploy a dehumidifier oi the adsorption type employing a solidadsorbent, such for instance as silica gel. Certain liquids, such aslithium chloride and calcium chloride may be used, instead of solidmaterial if desired, the thermal changesv taking place being ofpractically the same value. In the latter case the action is chemicalrather than physical, and hence it is not strictly proper to refer tosuch a dehumidifier as of the absorption type, but it is to beunderstood that these two forms of dehtunidifier are equivalent for thepurposes of the present application.

Referring particularly to the action of a dehumidifier using silica gel,when air containing water vapor is brought into contact with the silicagel the water vapor is in effect condensed within the pores of the gel.This results in the liberation of the latent heat of the water vaporremoved, so that the air issues from the gel dried, but with itssensible heat increased by an amount equal to the latent heat of themoisture removed, this being approximately 1,100 B. t. u. per pound ofwater vapor removed. In addition the heat of adsorption is liberated andgoes to heat the air, this being of the order of 200 B. t. u. per poundof water vapor. In conventional dehumidifica tion apparatus of this typethis latent heat (transformed into sensible heat) is removed by passingthe dried air over coils containing cooled water. However, if the air isnot cooled after being dehumidified, but is discharged dry and hot intoa given space, it will warm that space as well as lower its humidity.When using a dehumidifier of the adsorbent type in the usual manner,even more heat than is above indicated is in effect available for use.In practice, in a dehumidifier there are two or more bodies or beds ofsilica gel. While one of these beds is drying air, the other is itselfbeing dried by the application of heat, as by passing through it amixture of air and the products of combustion of a gas fire, suflicientair being used to give a mixture temperature of about 4 350. Thisprocess is called reactivation. At its conclusion the gel will be ratherwarm, and when it is again used to adsorb moisture, some of this heat inthe gel will be imparted to the air. In the'actuai dehumidification thedried air leav- 112% the apparatus is at a temperature of about F.Referring to Fig. 1 of the drawings, l0 indicates a room or space whichis to beair conditioned. Fresh air in suflicient amounts to meet theventilation needs of the space is drawn in through duct II by the actionof a fan i2 mounted at the entrance to a dehumidifier l3. The dried airleaving the dehumidifier passes by way of a conductor |4 through an aircooler l5 in which is located a radiator, indicated diagrammatically atl6. In our system the cooler l5 may or may not operate, depending uponthe temperature conditions in the space In. The air delivered from thecooler l5 enters a mixing'chamber I1, where it is mixed with a largerstream of recirculated air being drawn by a fan |8 through duct l9 fromthe space H), and discharged back into the space through a duct 28.Immediately following mixing chamber -|1 is an air cooler 2|, in

-which there is located another radiator 22 through which we may causeto flow cool water or any available refrigerant. If desired, a heater 23supplied with fuel through a pipe 24 may be placed in the duct followingair cooler 2| for a purpose later to be described. This heater may be ofany appropriate type, such as a gas heater indicated in the drawiiigs,or a steam or hot water coil. Cooler l5 will usually be supplied withwater from city mains or a well through pipe 25.

Returning now to the dehumidifier l3, which is shown diagrammatically,there are silica gel beds 26 and 21 which are used alternately as airdriers. 28,28, 30 and 3| are four swinging deflectors or valves whichare caused to take the full line and dotted line positions alternatelyat regular intervals while the dehumidifier is in operation. The conduitl4 connects with the right side of the dehumidifier through an opening32. A similar opening 33 in the left side connects with a conduit 34 inwhich is located a fan 35. A gas burner 38 fed by a fuel line 31produces a flow of hot air and gas of a temperature approximating 350 F.upwardly through conduit 38 into the dehumidifier casing. This heatedair and gas is the reactivating medium, and the conductor 34 is theexhaust pipe for that medium. It may include an enlarged section 39 inwhich is located a radiator 40 by means of which some of the heat of theexhausted reactivated medium may be absorbed.

When the valves of the dehumidifier are in the full line position freshair is caused to flow through silica gel bed 26, by which it is dried,and then out through opening 32 and conduit l4, as indicated by thearrows; At the same time hot reactivating medium flows in the oppositedirection through the lower part of the casing and through gel bed 21,driving out the moisture previously adsorbed by that bed, and passes outthrough opening 33 and conductor 34, the fan 35 assuring the flow. Whenthis has continued for a predetermined length of time the valves areautomatically thrown to the dotted line position, whereupon the freshair flows toward the right through gel bed 21 and out to therecirculating system, while the hot air for reactivation flows towardthe left through gel bed 25 and out through opening 33 and conductor 34.

In fuel pipe 31 we locate an electric valve 4|. A similar valve 42 isused in pipe 25 leading to radiator It. From that radiator there extendsa pipe 43 in which'there is a hand valve 44 which, when opened, permitsthe cooling water flowing through the pipe to pass to the drain.

Another pipe 45 in which there is a hand valve 46 connects with pipe 43and with radiator 48, so that when the valve 44 is closed and the valve46 opened the warm water from radiator I6 is it is further heated andthen carried by pipe 41 to a suitable storage tank 48, from which it maybe drawn for use directly or for still further heating, as may berequired.

The radiator 22 is fed by a pipe 49 having an electric valve 58 therein,and the cooling medium delivered from the radiator is discharged to thedrain or otherwise through a pipe 5|. Another electric valve 5| controlsthe flow of fuel to the heater 23.

The instruments by means of which the system is automatically controlledmay be located as found desirable or convenient either in the space IDor in a conductor forming part of the path for the recirculated air. Inthe drawing they are shown in the conduit l8. They consist of ahumidostat 52 and three thermostats 53, 54 and 55.- These instrumentsmay be of conventional form. An example of 'a humidostat which issuitable for the purpose is illustrated however in Fig. 3, where 56 is atape which expands and contracts as the humidity of the air in contactwith itincreases or decreases. This tape is secured at one end in anadjustable anchoring means 51, and at the other end in a lever 58pivotally mounted at 59. 60 and 8| are flexible electrical conductorswhich have terminals in a mercury tube switch 52 which is tiltablymounted at 63 and is adapted to be swung to circuit closing position bythe action of a spring 64 when the tape 56 expands to a predeterminedextent due to a rise in humidity, and

to a circuit opening position by the contraction of tape 58 when thehumidity falls sufficiently. Terminals 55 and 66 of the humidostat areconnected by electrical conductors 61 and 68 into the control system, aswill presently be described.

A duct 63 may be provided with connections as shown if it is desired todirect some recirculated air to the dehumidifier during periods ofextreme outdoor moisture, so as to lighten the load 0 the dehumidifier.

Referring to Fig. 2, two electric service wires are indicated at 18 and1|. Connected to these wires are two conductors 12 and", forming acircuit to supply energy to the primary coil 14 of a step-downtransformer. The-secondary coil 15 forms a part of a low voltage circuitincluding conductors 16 and 11 across which the conductors 61 and 68 arebridged. In this same circuit there is an electromagnet 18 controlling aswitch 18 which is adapted to open or close a circuit comprisingconductors and 8| and a motor 82. The motor 82 is the dehumidifier motorwhich operates the fans l2 and 35, and by means of cams or othersuitable mechanism shifts valves 28, 29, 38 and 3|- back and forth atregular intervals between their full line and dotted line positions,respectively. Branch conductors 83 and 84 serve to energize a magnetcoil 85, which opens gas valve 4|. Other branch conductors 86 and 81lead to an electromagnet 88 which controls a switch 89 to which we willrefer again later.

Bridged across the low voltage conductors 18 and 11 in a line parallelwith the line through humidostat 52 are two conductors 98 and 8| whichare adapted to be connected together by thermostat 54 when thetemperature in the premises falls to or below a predetermined point. Itwill be apparent therefore that the dehumidifier isarranged to bestarted either by the humidostat or bythe thermostat 54, and that itwill operate if the temperature becomes low enough,

whether or not the humidity conditions are such as would cause thehumidostat to function.

The thermostat 54 is a double contact thermostat, one contact 92 beingthe terminus of conductor 9i and the other contact 93 being connectedwith a low voltage conductor 94 which extends to one side of switch 89.From the conductor a conductor 95 extends to the secondary coil 96 of astep-down transformer, the primary coil 91 of which takescurrent fromthe line wires 10 and Ii through conductors 98 and 99. The other side ofcoil 96 is connected by means of a conductor I00 with an electromagnetBM controlling the valve 42 in the cooling water line 25. Magnet I0! isalso connected by a conductor I02 with the other side of switch 89. Itwill be apparent therefore that when the thermostat 54 moves to theright because of rising temperature, and engages contact 93, a currentwillbe set up through electromagnet it! provided that switch 89 isclosed at the time. But the switch 89 is closed only when switch 19 isclosed and the dehumidifier is in operation. Two conditions aretherefore necessary before cooling water will flow through pipe 25,first the dehumidifier must be in operation, and second the temperaturein the premises must be above a predetermined point. In somelocalitieswhere the heat requirements are small, heater 23 may be omitted. When itis used the valve 5| is controlled by an electromagnet I03 which isconnected on one side by a conductor M with line wire Ill, and on theother side by a conductor N35 with a contact Wt adapted to be closed bythermostat 55 when the temperature in the premises falls below apredetermined point, the other side of the thermostat being connected bya conductor IM with line wire I l. Through the pipes 49 and iii anysuitable refrigerant may be conducted to and away from radiator 22. Thefunctioning of this radiator is controlled by valve 50, which may beopened electrically by a magnet it which is in circuit with line wire Hthrough a conductor W9 and with line wire it through conductors Mil andill and the thermostat 53. When the room temperature rises above apredetermined point the thermostat 53 engages its contact M2, whereuponelectromagnet tilt is energized and the valve 50 is opened permittingrefrigerant to flow through the radiator.

By the proper selection or adjustment of the thermostatic controldevices the range of action of the heater 23 and of the two coolingradiators l6 and 22 can be regulated to suit requirements. We prefer toso select and adjust the parts that the heater 23 will be turned on onlywhen a relatively low temperature is reached in the premises, and willbe turned ofi slightly before the desired temperature is attained. Wealso prefer to have the radiator l6 function normally as an intermediaterange cooler for the dried air issuing from the dehumidifier, whichcooler will be turned off automatically when small increases intemperature are called for. The radiator 22 in which refrigerantcirculates we prefer to call into play only when the temperature isrelatively high, that is, such that the radiator I6 is not able byitself to accomplish the desired result.

Variations from the described structure may be employed. Accordingly, wedesire it to be understood that the scope of the invention is to beregarded as defined exclusively by the appended claims rather than bythe foregoing description or the accompanying illustration.

Having thus described our invention, we claim:

1. In an air conditioning system, means for recirculating air,'adehumidifier of the adsorption type arranged to deliver air into saidrecirculating system, a cooling means for the air delivered by thedehumidifier, and thermostatic means responsive to temperature changesonly for controlling said dehumidifier and said cooling means,

acting to cut off the cooling means whereby the when the temperaturefalls to a lower predetermined level. I

3. In an air conditioning system, means for recirculating air, adehumidifier of the adsorption type arranged to deliver air to saidsystem, means for heating the recirculating air, and

thermostatic means responsive to temperature changes only for startingsaid dehumidifier when the temperature in the premises falls to apredetermined level and for starting said air heating means when thetemperature falls to a lower predetermined level.

4. In an air conditioning system, means for recirculating air, adehumidifier of the adsorption type arranged to deliver air to saidsystem, a heater and a cooler for the recirculating air, andthermostatic means responsive to temperature changes only for disablingsaid cooler when the temperature in the premises falls to apredetermined level, for starting said dehumidifier when the temperaturefalls to a lower predetermined level, and for-starting said air heaterwhen the temperature falls to a still lower predetermined level.

5. In an air conditioning system, means for recirculating air, adehumidifier of the adsorption type arranged to deliver air to saidsystem, a humidostat and a thermostat arranged in parallel for causingsaid dehumidifier to function, not only when the humidity in thepremises is high, but also whenlthe temperature in the premises is lowirrespective of the humidity.

6. In an air conditioning system, means for recirculating air, adehumidifier of the adsorption type arranged to deliver air to saidsystem, a cooler for the air delivered by the dehumidifier, a humidostatadapted to start said dehumidifier when the humidity in the system risesto a pre determined percentage, and a thermostat acting in conjunctionwith said humidostat for controlling said cooling means adapted to setit in operation only when the dehumidifier is in operation and thetemperature of the premises is at or above a predetermined point.

7.. In an air conditioning system, means for recirculating air, adehumidifier of the adsorptiontype arranged to deliver air tosaidsystem, a cooler for the air delivered by the dehumidifier, and a doubleelectrical control for said cooler, one element of said control openingand closing with the starting and stopping of the d ehumidifier and theother element closing and opening with the rise and fall of thetemperature in the premises with respect to a predetermined temperaturelevel.

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8. In a control system for air conditioning means, a.dehumidifier, acontrol circuit therefor, two parallel lines bridged across said controlcircuit, each of said parallel lines having switches, a humidostatadapted to close one of said switches when the humidity rises aboveapredetermined point, and a thermostat adapted to close the other switchwhen the temperature falls below a predetermined point.

9. In an air conditioning system, means for recirculating air, adehumidifier of the adsorption type arranged to deliver air into saidrecirculating system, a cooling means for the air delivered by thedehumidifier, humidity responsive means for controlling saiddehumidifier, and thermostatic means for controlling said dehumidifierand said cooling means, said thermostatic means acting to start thedehumidifier and ,to prevent the cooling means from operating when thetemperature of the system falls below a predetermined point, regardlessof the condition of the humidity responsive means.

10. In an air conditioning system, means for recirculating air, a firstcooling means for cooling said air, thermostatic means for starting saidfirst cooling means at a relatively high temperature and stopping it ata slightly lower temperature, a dehumidifier of the adsorption typearranged to deliver air to said recirculating system, a second coolingmeans for the air delivered by said dehumidifier connected to operateonly when the dehumidifier is operating, a humidity responsive device tostartand stop said dehumidifier and second cooling means atpredetermined relative humidities in the system, thermostatic means fordisabling said second cooling means at a predetermined low temperatureand for setting it in operation at a slightly higher temperature, andfor starting said dehumidifier and holding said second cooling meansdisabled-at said predetermined low temperature regardless of thecondition of the humidity responsive device and for stopping it at aslightly higher temperature.

11. In an air conditioning system, means for recirculating air, a firstcooling means for cooling said air, means for heating said air,thermostatic means for starting said first cooling means at a relativelyhigh temperature and stopping it at a slightly lower temperature,thermostatic means for starting said heating means at a relatively lowtemperature and stopping it at a slightly higher temperature, adehumidifier of the adsorption type arranged to deliver air into saidrecirculating system, a second cooling means for the air delivered bysaid dehumidifier connected to operate only when the dehumidifier isoperating, a humidity responsive device to start and stop saiddehumidifier and second cooling means at predetermined relativehumidities in the system, intermediate temperature thermostatic meanswhich will disable said second cooling means at a predeterminedintermediate temperature and will cause it to operate at a slightlyhigher intermediate temperature, and which will JAMES c. PATTERSON.WlLLET E. STARK.

